Synchronizing device in a vehicle gearbox

Abstract

A synchronizer in a vehicle gearbox includes a synchronizing ring and a torque-transmitting element, which transmits a torque from the synchronizing ring to an engaging sleeve in such a manner that the engaging sleeve is imparted an extra force in the engaging direction.

What is claimed is: 
     
       1. Synchronizer in a vehicle gearbox comprising a guide sleeve, intended to be non-rotatably joined to a shaft in the gearbox, an engaging sleeve which is non-rotatably, but axially displaceably, mounted on the guide sleeve, an engaging ring provided with exterior engaging teeth and which is intended to be securely joined to a gear rotatably mounted on said shaft and is lockable relative to the guide sleeve by axial displacement of the engaging sleeve from a neutral position to an engagement position, in which interior engaging teeth on the engaging sleeve engage the exterior teeth on the engaging ring, and a synchronizing ring cooperating with the engaging sleeve and the engaging ring, said synchronizing ring having a conical frictional surface which is movable to engagement with a facing conical frictional surface on a ring rigidly attached to the engaging ring, means being arranged to amplify the engaging force upon displacement of the engaging sleeve from the neutral position to an engagement position, wherein the synchronizing ring (9;34) is fixed rotationally relative to a torque-transmitting element (20;31), which is axially movable relative to the synchronizing ring and has cam surfaces (25;37) which cooperate with cam surfaces (26;38) on the engaging sleeve (4) and which upon relative rotation between the torque-transmitting element and the engaging sleeve, caused by frictional engagement between the frictional surfaces of the synchronizing ring and the engaging ring, create a force acting on the engaging sleeve in the engaging direction. 
     
     
       2. Device according to claim 1, wherein the torque-transmitting element (20) is movable in the direction away from the synchronizing ring against the effect of a spring force. 
     
     
       3. Device according to claim 2, wherein the torque-transmitting element (20) has engaging teeth (27) engaging grooves (28) in the synchronizing ring (13) and radial fingers (22) received in slots (23) in the guide sleeve (1) and that said cam surfaces (25) are formed at distal ends of the fingers. 
     
     
       4. Device according to claim 3, wherein each finger (22) at its distal end has a heel (24), which is made with a pair of V-oriented cam surfaces (25) facing the synchronizing ring, and that the engaging sleeve (4) for each heel has a pair of cam elements (14), which, in the neutral position, lie on either side of the associated heel and each have a cam surface (26) complementary to the facing cam surfaces (25) on the heel. 
     
     
       5. Device according to claim 3, wherein compression springs in the form of spring washers (30) are arranged between an abutment surface on a sleeve of the torque-transmitting element (20) and a facing surface on the guide sleeve (1). 
     
     
       6. Device according to claim 1, wherein the torque-transmitting element (31) comprises a sleeve (32) with a number of inner fingers (33), which are axially movable relative to, but are rotationally fixed relative to, the synchronizing ring (34), and with a number of outer fingers (35), which at their ends have V-oriented cam surfaces (37) cooperating with the cam surfaces (38) of the engaging sleeve.